1. Field of the Invention
This invention relates to electric drills used for producing circular holes in workpieces, and more particularly concerns a device to facilitate vertical alignment of the drill with the workpiece.
2. Description of the Prior Art
Hand held electric drills are widely used for producing circular holes in workpieces. It is generally sought to produce holes which are perpendicular to the surface of the workpiece. Proper alignment of the drill to produce such perpendicular holes is difficult. Even if such alignment is fortuitously established at the initiation of the drilling of a hole, alignment of the drill may change during the drilling operation.
Attempts to alleviate this problem have resorted to the use of frameworks which secure the electric drill and guide the motion toward the workpiece. Such framework devices are however unwieldy, and are particularly cumbersome when many holes must be drilled.
Other efforts to align the drill have involved the incorporation of a carpenter's type air bubble sight glass often called a spirit level into the drill. However, the use of a level detector device is effective only when the workpiece surface is horizontally disposed; and in fact a separate leveling device is then needed to assure the horizontal disposition of the surface of the workpiece.
Because the location of such spirit levels is removed from the actual site of drilling, it is difficult for operator to continuously observe both the level and the site of drilling during the drilling procedure. Errors further occur because of parallax distortion in viewing the spirit level, and the fact that extremely slight displacement of the air bubble within the confining sight glass tube or dome is equivalent to a large departure from perpendicular.
It is accordingly an object of the present invention to provide a device for aligning a hand-held electric drill perpendicular to a work surface.
It is a further object of this invention to provide a device as in the foregoing object wherein the operator's visualization of perpendicularity is directly upon the workpiece.
It is another object of the present invention to provide a device of the aforesaid nature which enables the operator of the drill to continuously monitor alignment while drilling a perpendicular hole.
It is a still further object of this invention to provide a device of the aforesaid nature which is easily attachable to any drill and does not encumber normal operation of the drill.
These and other beneficial objects and advantages will be apparent from the following description.